Artificial tooth



March 22, 1932. Q L R S 1,850,889

ARTIFICIAL TEETH Filed June 26, 1929 Patented Mar. 22, 1932 UNITED s ATEs PA ENT oHARLRs- L. MoRRIs, or ooLUMRUs, OHIO, ASSIGNOR TO THE COLUMBUS DENTAL t;

MANUFACTURING COMPANY, OF COLUMBUS; 01110, A CORPORATION ARTIFICIAL TOOTH Application filed June 26,

Interchangeability in artificial teeth is a recognized necessity in crown and bridge Work. Dental porcelain shrinks in size from approximately to between the 5 molded biscuit form and the baked tooth.

This produces a wide range of variation, curvatures and distortions, which can be overcome only by grinding the contact portions of the baked tooth to exact standard, so that w in case of breakage one tooth can be replaced by another restoring the case to its original condition, without removing the bridge.

' The high temperature necessary to the baking of a tooth prohibits the placing of metal in the biscuit because the metal will fuse or become so distorted that it is of no use as a fastening element in an interchangeable tooth, and it frequently distortsthe biscuit to such an extent that it is useless.

The process of making porcelain teeth or facings accurately interchangeable is an expensive one inasmuch as the contacting surfaces of the tooth must be carefully and accurately ground, then the slots and post hole must be ground with the same accuracy, all

process.

the tooth to the same.

In the drawings;

Figure 1 is a side elevation of a tooth embodying my invention.

Figure 2 is a vertical section of the same 3 with the post added in elevation.

Figure 3 is a side elevation of the backing. partly 1n section.

Figure. 4 1s a vertical sectlonal View of a no tooth showing another embodiment and a post in elevation adapted to this form.

. gage a groove in the bridge or cap to anchor 1929.. Serial n. 373,890. 7

Figure 5 is a transverse sectional View of the post shown in. Figure 2.

Figure 6 is a side elevation. of the post shown in Figure 2 detached.

Figure 7 is a rear elevation of-the tooth shown in Figure 1.

In carrying out my invention I first form a biscuit in the usual way and make certain recesses or slots in the surfaces that are designed to contact with the cap on the bridge or crown on which the tooth is designedto be anchored, I then bake the biscuit in the usual way, and naturally there will be some dlstortion in the tooth and recesses. I then grind the contacting surfaces 1 and 2 of the tooth 3 to flat planes; the recesses 4, 5, may or may not require reaming, but in the event that they do it will be a comparatively inexpensive operation to do this.

I provide an anchoring post 6 of metal having a tongue. or lug, 7 which is adapted to be seated in the recess 4, while the labial, end of the post 6 is seated in the recess 5, the

recesses being of greater diameter than the post and-its tongue. I now place a porcelain 8 of lower fusing temperature than the porcelain of the tooth body in the recesses 4 and. 5 which is packed tightly in the recesses around the tongue 7 and the labial end of the post.

The article thus prepared is placed in a baking oven and held there until this lower fusing porcelain 8 has fused, or baked, within the recesses and around the tongue 7 and labial end of the post 6, thereby rigidlv and securely locking the post to the porcelain tooth or facings. The metal of which the post is formed has a fusing point not afl'ected'by the fusing temperature of the porcelain 8, therefore there is no danger of the post distorting while the porcelain 8 is fusing and being baked. v I

The grinding of the contacting surfaces may be done before the post 6 is attached to the tooth as the low fusing temperature of porcelain 8 will not affect these surfaces after they have been ground.

After the metal post has been worked by suitable tools to an accurateinterchangeable size and fit the tooth is ready for use.

- The cost of grinding or otherwise accurately shaping the post 6 is very slight because it is metal and consequently will not appreciably dull the tools used for that purpose; Whereas, in the formation of the slots and holes in porcelain teeth heretofore practiced the porcelain being hard quickly dulled the tools which necessitated frequent sharpening and adjustments.

My invention further consists in forming a backing 9 to fit and be used with my improved tooth, said backing having contacting surfaces 10, 11, adapted to engage the surfaces 1 and 2 of the tooth. In the surface 11 I form a post hole 12 complementary in shape to the post 6. This post hole is opened up to the surface 11 by means of a slot 13 of less diameter than the post hole which receives the web 14 of the post, whereby there is ample metal between the post hole and the face 11 to resist incident strains and stresses. The backing is accurately fitted for interchangeability with the porcelain tooth before the tooth and backing leave the factory, therefore the dentist, or the laboratory, purchasing them is assured of accurate interchangeability and his labors are proportionately reduced.

The angularity of the recesses 4 and 5 with reference to surfaces 1 and 2 may be changed at will, and the parts of the post engaging the recesses correspondingly changed.

The tooth may be provided with a recess 15 of the shape or formshown in Figure 4, and the post 6 provided with a complcmen tary labial end 15.

While I have specifically referred to the porcelain 8' as a desirable element to anchor the post to the tooth, it will be understood that other substances may be used.

It is impossible to standardize accurately a tooth having metal fastening elements baked in it. I overcome this by standardizing the contacting surfaces of the baked tooth before I attach the metal fastening element.

I am aware that changes may be made in the details shown without departing from the spirit of my invention and the scope of the appended claims.

What I claim is:

1. The method of making an interchangeable tooth which consists in making a biscuit to form integrally homogeneous lingual and labial portions and a root section having intersecting contacting surfaces and recesses in said surfaces, baking the biscuit, standardizing the contact surfaces after the tooth is baked, fitting portions of an anchor in said recesses, filling said recesses with a material having a lower fusing temperature than that of the body of the tooth, again baking the tooth to fuse said material and permanently lock the anchor tothe tooth body, and then standardizing the anchor relative to the standardized contacting surfaces.

2. The method of making an artificial tooth having a porcelain root which consists in forming the lingual and labial portions and root section in one homogeneous mass, shaping the tooth with a lingual overhang portion, forming recesses in the occlusally directed end of the overhang portion then completely baking the tooth, then filling the said recesses with a low fusing porcelain, embedding a backing anchor in said low fusing porcelain in the recesses, then again baking the tooth to fuse said low fusing porcelain to permanently lock said anchors in said recesses, and then standardizing the backing anchor relative to the contacting surfaces of the tooth.

3. The method of making an interchange able tooth, which consists in shaping a biscuit to form integrally homogeneous lingual and labial portions and a root section having contacting surfaces and an anchor receiving recess, baking the biscuit, standardizing the contact surfaces after the tooth is baked, fitting an anchor in the recess and filling said recess with a substance having a lower fusing temperature than that of the body of the tooth, again baking the tooth to fuse said substance and thereby permanently lock the anchor to the tooth body, and then standardizing the anchor relative to the standardized contacting surfaces.

4. The method of making an interchangeable tooth, which consists in forming a biscuit of labial and lingual portions and a root section in a homogeneous mass, to provide contact surfaces, forming a recess opening through one of said surfaces, baking said biscuit, standardizing said contact surfaces, filling said recess with a low fusing substance, embedding a portion of a backing anchor in said fusing substance, again baking the tooth to fuse the fusing substance and to thereby lock the anchor portion therein, and then standardizing the backing anchor relative to said contact surfaces.

In testimony whereof I affix my signature.

CHARLES L. MORRIS. 

